부산대학교 도서관

Dynamic impact response of coextruded 2048-layer composites consisting of alternate layers of ductile polycarbonate (PC) and brittle polymethylmethacrylate (PMMA) with various layer configuration was examined using the compression split Hopkinson bar (SHB) technique. The dynamic stress-strain measurements revealed that the apparent yield (maximum) stress of these co-extruded composites was strongly dependent upon the relative thicknessses of PC and PMMA layers. PC/PMMA multi-layers with 5, 10, and 20 volume-percent (vol.%) of PMMA yielded at stresses comparable to that of the all PC sheet (PC-control); however, the yield stress values were significantly higher for the composites with less than 80 vol.% PC. Increasing the PMMA layer thickness and decreasing the PC content significantly increased the yield stress of PC/PMMA laminates. The SHB data correlated very well with deformation behavior observed in the PC/PMMA composites subjected to fragment-simulating-projectile (FSP) impact. Composites with less than 80 vol.% PC failed in a brittle mode. Ductile deformation, a predominant mode of failure in PC, was observed in the composites with 90 and 95 vol.% of PC; however, a mixed mode of failure occurred in the composite with 80 vol.% of PC. [ABSTRACT FROM AUTHOR]